This invention relates to a solar energy collector and particularly to one comprising the evaporator of a heat pipe type heat transfer system.
For certain types of solar energy conversion systems radiant solar energy is concentrated onto a collector. This input heat is used to evaporate the working fluid within a heat pipe. In one application, the heat pipe is used to transfer heat to a Stirling cycle engine which can be used to drive an electrical generator or another load. In order to collect a significant amount of solar energy, a very large parabolic reflector is used which concentrates the radiant energy onto the collector. The collector is a hollow housing with a concave surface which receives the radiant energy. Significant design problems are encountered in the design and fabrication of solar energy collectors of this type since they are exposed to significant thermal stresses during operation and must withstand external atmospheric pressure forces since many heat pipe systems operate at internal pressures below atmospheric, for example, when sodium is used as a heat transfer material below 875.degree. C. Particular structural problems occur at the joints between components of the collector housing.
This invention is directed to an improved solar energy collector of the type described previously having a configuration which minimizes mechanical stresses on the collector at its radially outer peripheral edge. The solar collector according to this invention further includes numerous layers of fine wire mesh which are in intimate contact with the inside surfaces of the hollow solar collector which serve to distribute heat pipe working fluid in the liquid state over the surfaces of the solar collector so that the liquid can be efficiently vaporized.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.